Fluid circulating device



y 4 1944- w. H. KUSTER ET AL 2,352,792

FLUID CIRCULATING DEVICE Filed Aug. 7, 19 42 llllllll/I/llll INVENTORS ZDmJLXusier Edwin 5.6251722:

, ATTORNEYS Patented July 4, 1944 UNITED STATES PATENT OFFICE FLUID CIRCULr QTING DEVICE William H. Kus ter, San Francisco, and Edwin A.'Glynn, 'Lodi, Calif.

Application August '7, 1942, Serial No. 454,061

3 Claims. #31. 230-95) This invention relates to a fluid circulating system, the main object being to provide a device, adapted to be interposed in the line of pressure flow of a fluid from a source of pressure to a closed vessel, by means of which fluid already in the vessel may be circulated from the vessel, through a portion of the line and back to the vessel without the use of a fan or other mechanical circulating means, and which will provide for a rapid circulation and a large volumetric flow of the circulating fluid.

The device has been particularly designed for use in connection with the deoxygenizing apparatus of our copending application, Ser. No. 453,930 /2, filed August 7, 1942, to withdraw the air initially in the vulcanlZing vessel of the apparatus, circulate such air through a portion of the incoming gas line and back to the vessel and to transform the air into an inert gas while it is thus circulating.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects we accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

The figure on the accompanying drawing is or conduit, through which a heated gas flows and which terminates in a restricted outlet nozzle 2 preferably concavely curved on the outside. This nozzle projects and discharges into a relatively large cylindrical chamber 3 axially thereof.

A conduit 4 extends axially from the end wall ofthe chamber opposite the nozzle and in the present illustration leads to a closed container 5 having a catalyst therein, from which container another conduit 6 leads to the closed vessel 1 from which the circulation is to be eflected. The inner wall of the conduit is on a diverging slope away from the chamber or in the direction of flow, and the angle of divergenceis approximately the same as the angle A defining the edge or periphery of the stream or jet J leaving the nozzle, and which is approximately 14 for air at atmospheric conditions. This angle, however, is influenced by the form of the nozzle 2, the characteristics of the fluid passing therethrough, and other factors.

Said wall, however, while substantially parallel to the jet, is of greater diameter than said jet. The conduit joins the adjacent end of the chain'- her with an interior convex curvature of substantial radius, as shown at 8, in order to leave a considerable space lengthwise of the jet between the tip-of the nozzle and the adjacent end E of the straight diverging conduit wall.

' Suitably mounted in the chamber axially thereof between nozzle 2 and the curved wall 8 is a deflector or. flow guidin secondary nozzle 9 surrounding the adjacent portion of jet J and pointing toward conduit 4. This nozzle is formed with an interiorly convex and exteriorly concave wall, which at its base or large end is of relatively large diameter and'a radial line of the corresponding end of the curve is substantially parallel to the axis of the nozzle as shown.

From its outlet end, nozzle 9 extends lengthwise of jet J for a'short distance and is of somewhat greater diameterat said end-than jet J but smallerthan the diameter of conduit 4 at two mixing fluids, and its diameter relative to that of the adjacent portion of the jet is such that the entering air joins thejet as near the velocity of said jet as possible, so as to give a smooth flow.

A short distance back from said outer end, however, the diameter of nozzle 9 is slightly less than at said outer end, as indicated at L. In other words, nozzle 9 flares out slightly to its adjacent end from, point L.

The above mentioned distance is increased in cases where due to temperature diflerences and/ or flash evaporation or sudden condensation of one or the other of the constituents of the fluids, the resultant sudden disturbances in the flow can be overcome by a short confinement or even reacceleration' of the mingling fluids.

The edge of the small diameter end of nozzle 9 is sharpened and carefully designed to cause a shockless mixing of the fluids joining at this edge; the nozzle in cross section being substantially of airfo l form as shown, so as to avoid a tendency to recirculation of the air flowing over the outer face thereof.

A conduit Ill leads from the vessel 1 to the chamber 3 circumferentially thereof, so that the flow therefrom will be drawn into the space S between the back wall of the chamber and the nozzle 9, and also the space S between said nozzle and the opposite end wall of the chamber. The form and arrangement of nozzle 9, as above described. is for the purpose of assuring constant accelerat on of the cold air entering space S of chamber 3 from conduit Ill, having due regard to itsexpansion as it contacts and merges with the hot jet J, and the resultant contraction of the hot fluid, and so that such air enters the jet tangentially thereof so as to avoid shock.

The diameterof the nozzle at point L is proportionate'to the volumetric flow of air entering said nozzle, the flare to the outer end of the nozzle allowing for expansion of the air as it strikes the hot jet. In this manner, ample nozzle capacity for the combined flow is provided, without causing undue turbulence at that point, and which would of course reduce the efliciency of the apparatus by loss of energy in the jet in the space between nozzles 2 and 9.

The same is of course true of conduit 4, the diameter of which relative to the corresponding portion of jet J is such that it has sufiicient capacity not only to handle, without increase of jet pressure, not only the jet and air mixture passing through nozzle 9, but the additional air flow drawn in through space S as well; and also providing for temperature changes or changes of state.

The angle of divergence of conduit 4 is held within limits which offer the least possible resistance to the fluid 'flow, taking into consideration the specific volume changes of the fluids due to mutual mingling. heat losses, partial condensation or evaporation, etc. Also, the surface roughness. concentricity of the various parts of the device, material thickness at the point of confluence, flow uniformity, temperature changes, etc, must all be considered in determining the nozzle areas, the nozzle and vane shapes, and the angle of divergence and the axial spacing of the vanes. A further limiting factor concerning this angle of divergence is the surface roughness at the expanding cone, where the fluid regains pressure as its flow is retarded without permitting turbulence.

The difference in spacing lengthwise of the jet between nozzles 2 and 9 and between nozzle 9 and conduit 4 is designed so as to be proportionate to the difference in size of the corresponding portions of the jet stream and the relative difference in the pressures, temperatures, densit es, viscosities. surface tensions and particularly the velocities thereof.

Due to the fact that the flow from conduit I enters the jet in the zone of its maximum velocity and therefore minimum pressure, not only is a rapid withdrawal of a r from said conduit assured, giving the desired rapid circulation to and from the vessel, but a considerable volume of air is handled, due to the total area of the jet which is exposed to the air from conduit 10 and which is confined in chamber 3 about the jet.

While we have here shown only one auxiliary nozzle 9, more of the same may be used, in a correspondingly longer chamber 3, if desired, as long as a sufliciently low pressure can be maintained at the last nozzle in the direction of flow to draw fluid. from conduit I0. Otherwise, recirculation within chamber 3 would result, with corresponding loss of kinetic energy, originally imparted to the fluid of jet J by combustion and consequent gas expansion. This kinetic energy in the ideal case is completely converted into pressure when the mixed gases leave conduit 4.

From the foregoing description it will be readily seen that we have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from .such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described our invention, what we claim as new and useful and desire to secure by Letters Patent is:

1. A fluid circulating device comprising a chamber, a primary nozzle projecting into said chamber, a conduit leading from the chamber on the side thereof opposite said nozzle and in substantially axial alinement with such nozzle, a secondary nozzle disposed within the chamber and having an interior convex and an exterior concave wall, the restricted end of the secondary nozzle surrounding and spaced from a hypothetical conoidal body which would be formed by a jet issuing from the primary nozzle, the

enlarged end of the secondary nozzle being of such a relatively large diameter that a radial line drawn from the center of curvature of such enlarged end to the outer edge thereof will'lie substantially parallel to the longitudinal axis of the primary nozzle, and a fluid inle t member connected with said chamber independently of the primary nozzle.

2. A fluid circulating device comprising a. chamber, a primary nozzle projecting into said chamber, a conduit leading from the chamber on the side thereof opposite said nozzle and in substantial axial alinement therewith, the walls of the conduit lying parallel to and spaced from a hypothetical conoidal body which would be formed by a jet issuing from the primary nozzle, a secondary nozzle disposed within'the chamber between the primary nozzle and the conduit, such secondary nozzle having aninterior con vex and an exterior concave wall, the restricted end of the secondary nozzle surrounding and extending lengthwise of such hypothetical body and being of a slightly greater diameter than such body but of a lesser diameter than said conduit, and a fluid inlet member connected with said chamber independently of said primary nozzle.

3. A fluid circulating device comprising an initial pressure-flow line terminating in a primary nozzle, a relatively large cylindrical chamber surrounding said nozzle axially thereof, an outlet conduit leading from the chamber in axial alinement with the primary nozzle, the walls of the conduit lying parallel to and spaced from a hypothetical conoidal body which would be formed by a jet issuing from the primary nozzle, the inner end of the conduit being joined to the chamber walls by convexly curved walls of substantial radius to form a considerable space between the end of the primary nozzle and the outlet conduit about the hypothetical conoidal body, a secondary nozzle within the chamber and having an interior convex and an exterior concave wall, the restricted end of such secondary nozzle surrounding and spaced from such hypothetical body and being of a diameter less than the conduit, the enlarged end of such secondary nozzle surrounding and spacedfrom the side walls of the primary nozzle and being of such a relatively large diameter that a radial line drawn from the center of curvature of such enlarged end to the outer edge thereof will lie substantially parallel to the longitudinal axis of the primary nozzle, and an inlet conduit adapted to admit fluid to the chamber independently of such primary nozzle.

WILLIAM H. KUSTER; EDWIN A. GLYNN. 

